Catalyst for reacting carbonitriles

The present invention relates to a catalyst for reacting carbonitriles with water, wherein the catalyst comprises at least 60% by weight of manganese dioxide with an empirical formula MnOx where x is in the range from 1.7 to 2.0, and at least one plasticizer. The present invention further relates to a process for preparing the catalysts detailed above and to a process for preparing carboxamides by reacting carbonitriles with water in the presence of the present catalyst.